Label dictionaries

[teunbrand]

I recently saw this tweet, which I thought was a nice suggestion, because it allows you to reuse labels without falling victims to typos and such. It still required a lot of manual management though.

Then, I realised we have several related issues/feature requests already, for example #4631 or #4313. However, I think having a label dictionary is perhaps a more elegant approach than hardcoding a path to retrieve labels from attributes (see also #4631 (comment)).

For the vanilla case, I think it should work something like this:

library(ggplot2)

label_dictionary <- c(
  displ = "Engine displacement [L]",
  hwy   = "Highway miles per gallon",
  "factor(cyl)" = "Number of cylinders" # Maybe I should be able to omit the function call?
)

# What I would like to specify
ggplot(mpg, aes(displ, hwy, colour = factor(cyl))) +
  geom_point() +
  labs(dict = label_dictionary)

# What I would want it to look like
ggplot(mpg, aes(displ, hwy, colour = factor(cyl))) +
  geom_point() +
  labs(!!!setNames(label_dictionary, c("x", "y", "colour")))

^{Created on 2023-02-05 with reprex v2.0.2}

However, for the {Hmisc/tinylabels/labelled/sjlabelled} cases, we might be able to specify dict = derive() (or similar) to specifically instruct to lookup label names in the data.

[aphalo]

@teunbrand This feature will be very useful! It will allow me to not only to simplify the code in 'ggspectra' but, more importantly, easy my plans to implement support for multiple languages.

[teunbrand]

I'm glad you can see the potential! If you want to give it a spin before it hits the main branch, you can use pak::pak("tidyverse/ggplot2#6077") to install that functionality.